arXiv:2409.02802cs.LGcs.CR2024-09被引 2

通过自集成降低分类边界方差,提升时间序列分类的可认证鲁棒性。

Boosting Certified Robustness for Time Series Classification with Efficient Self-Ensemble

  • 利用自集成方法减少分类边界方差,增强预测置信度下界。
  • 在多个时间序列分类数据集上实现更大可认证扰动半径,优于现有方法。
  • 计算开销低于深度集成,适合实际部署,尤其适用于高鲁棒性需求场景。

近年来,时间序列分类中的对抗鲁棒性问题受到广泛关注。然而现有防御机制仍有限,对抗训练虽为主流但无法提供理论保证。随机平滑(Randomized Smoothing)因其能对ℓ_p球攻击提供可证明的鲁棒性半径下界而脱颖而出。尽管如此,当前研究多集中于时间序列预测,或在统计特征增强下的非ℓ_p鲁棒性设定。我们发现,在时间序列分类任务中,随机平滑表现平平,难以在鲁棒性较差的数据集上提供有效保证。为此,本文提出一种自集成方法,通过减小分类边界的方差,提升预测标签的概率置信度下界,从而获得更大的可认证半径。该方法同时缓解了深度集成(Deep Ensemble, DE)的计算开销问题,在保持竞争力的同时,在部分数据集上甚至超越其鲁棒性表现。理论分析与实验结果均验证了方法的有效性,相比基线方法显著提升了鲁棒性测试表现。

原文摘要 · Abstract (English)

Recently, the issue of adversarial robustness in the time series domain has garnered significant attention. However, the available defense mechanisms remain limited, with adversarial training being the predominant approach, though it does not provide theoretical guarantees. Randomized Smoothing has emerged as a standout method due to its ability to certify a provable lower bound on robustness radius under $\ell_p$-ball attacks. Recognizing its success, research in the time series domain has started focusing on these aspects. However, existing research predominantly focuses on time series forecasting, or under the non-$\ell_p$ robustness in statistic feature augmentation for time series classification~(TSC). Our review found that Randomized Smoothing performs modestly in TSC, struggling to provide effective assurances on datasets with poor robustness. Therefore, we propose a self-ensemble method to enhance the lower bound of the probability confidence of predicted labels by reducing the variance of classification margins, thereby certifying a larger radius. This approach also addresses the computational overhead issue of Deep Ensemble~(DE) while remaining competitive and, in some cases, outperforming it in terms of robustness. Both theoretical analysis and experimental results validate the effectiveness of our method, demonstrating superior performance in robustness testing compared to baseline approaches.

时间序列鲁棒性自集成可认证

Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。